Preparation Of β-naphthalene Sulfonate Formaldehyde Condensates And Its Application In One Bath One Step Dyeing Of Polyester/Cotton Fabrics

To achieve energy conservation,emissions reduction and clean production in the textile printing and dyeing industry,one-step dyeing of polyester/cotton fabrics with dispersed/reactive dyes has become an important dyeing technology in modern textile industry.Compared with traditional two-step dyeing methods,one-step dyeing can greatly save dyeing time and cost,reduce washing and cleaning steps,improve production efficiency,and also reduce wastewater discharge and environmental pollution.However,dyeing polyester with disperse dyes requires high temperature(130 ℃),and the reactive dyes need to be able to be resistant to high temperature.Improving the alkali stableility of reactive dyes at high temperature is important for increasing the utilization rate of reactive dyes and reducing the dyeing costs of polyester/cotton fabrics with dispersed/reactive dyes.In this paper,we prepared three β-naphthalenesulfonic acid formaldehyde condensates and used them as additives to complex with selected reactive dyes to study their dyeing performance on cotton fabrics at 130 ℃.Further research was conducted on their application performance in the one-step dyeing of polyester/cotton fabrics with dispersed/reactive dyes.Specifically,three β-naphthalene sulfonic acid formaldehyde condensates A1,A2,and A3 were prepared by changing the ratio of naphthalene and formaldehyde(1:0.25,1:0.50,1:0.75),and their degree of condensation was analyzed using infrared spectroscopy(FTIR),highperformance liquid chromatography(HPLC)gradient analysis,and viscosity testing.The results showed that the degree of condensation of the three additives was in the order of A3 >A2 > A1.The effects of A1,A2,and A3 on the surface tension of the solution were tested,and the results showed that the larger the degree of condensation,the stronger the reduction effect on surface tension.A1,A2,and A3 were then mixed with reactive dyes.Three new reactive dyes(reactive yellow-brown RE-ZY,reactive deep-brown RE-RY,and reactive deep-blue REBK)were selected,and the additives were added in proportions of 5%,10%,15%,20%,and100% of the weight of the reactive dyes to obtain the mixed reactive dyes.The blank control group was prepared by mixing the same amount of titanium dioxide with the reactive dye.The absorbance of the mixed dyes at the maximum absorption wavelength was measured,and the concentration of the original reactive dye powder was used as a standard for calculation.First,the dyeing performance of the mixed reactive dyes on cotton fabric was studied under the condition of 130 ℃,and it was found that A2 and A3 had good deepening effects on all three reactive dyes.When the proportion of additives was 20% and 100%,the deepening effect could be improved by 4%～5%,and the wet rubbing fastness and water washing fastness could be increased by half a grade.Furthermore,the three reactive dyes mixed with 20% and 100% of β-naphthalene sulfonic acid formaldehyde condensates A2 and A3 were used to dye polyester/cotton blended fabrics(50/50)and(40/60)using a one-step,one-bath dyeing method,and four colors were obtained: dark blue,black,dark gray,and brown.The results showed that the addition of A3,accounting for 20% of the dye mass,had the best deepening effect,and the rubbing fastness and washing fastness could also be increased by half a grade.Through cost accounting,the use of β-naphthalene sulfonic acid formaldehyde condensates prepared in this study can significantly reduce the amount of dyes used when dyeing to the same depth.Combined with the energy-saving and emission-reducing advantages of the one-step,one-bath method,it can further reduce enterprise costs and achieve good economic benefits.